1. Field of the Invention
Embodiments of the invention relate to the field of search engines, and more specifically, to content image search.
2. Description of Related Art
Search engines have been popular to retrieve information over the Internet in response to queries entered by a user. The retrieved information may be in the form of textual documents, a Hypertext Markup Language (HTML) page, an image, or a video clip. However, the queries are mostly in textual form entered as a keyword or keywords. In many applications, textual keywords may be inadequate or insufficient for searching. In some cases, the user may not even know the proper keywords to use. For example, the user may be watching a video content on a television and may be interested to retrieve information, either visual or textual, related to a particular image or a portion of an image shown on the display screen. The user may not know how to describe the image in textual form, or may not have an easy way to input this information into a text field (e.g., no keyboard when watching the TV).
Existing techniques for searching content images using a query image have a number of drawbacks. One technique takes a snapshot of a picture by a cell phone and sends the image to a server via the Web. The query image is separated into triplets. These triplets are then matched with those in a table containing a database of the training images. This technique does not work for content broadcast via a broadcast channel. It also requires the availability of an image database of training images which may be limited in size. In addition, the technique does not work for all types of images. Another technique combines modules for detecting 27 features of adult pictures and determines whether an image has an adult content so that it may be filtered out. This technique only examines the images returned by an image search. It does not use an image query for searching.